As Rep. Paul Ryan embarks on a national campaign, he will still have to run for re-election for his House seat.

Wisconsin law allows Ryan to seek both the vice presidency and another term in the House, and that is the understanding of what he will do, according to a Congressional campaign spokesman.

Ryan's 1st district includes Republican pockets in the southeastern part of the state, and he won re-election last cycle by a 2-to-1 margin. The district was improved for him in redistricting. All of these points indicate that his re-election race should not be competitive, and Roll Call rates this race as Safe Republican.

But even before Ryan was picked as the vice presidential nominee, Democrats were making noise about giving him more of a race than he's used to. He has a wealthy Democratic opponent, Rob Zerban, who has worked relentlessly to convince the political establishment that this is a real race. His argument is that Ryan has not had a serious opponent in years and that there is an opportunity for an organized Democrat to force an upset.

In an interview with Roll Call about a week ago, Zerban discussed the notion of Ryan as a vice presidential candidate. He argued that there is an opportunity for his campaign if that came to be. The logic is that he would have the district to himself while Ryan will be criss-crossing the country.

“Now that Paul Ryan’s personal ambition has clearly trumped his interest in the First District, I have no doubt he’ll find himself out of a job come November," Zerban said in a statement released this morning. "Once Wisconsinites and voters across our country learn the truth about Ryan’s radical plot to end Medicare as we know it, de-fund women’s health care, and preserve tax breaks for millionaires, they'll vote against him not just once, but twice."

"In the coming weeks, our campaign will work with President Barack Obama and Vice President Joe Biden to continue getting the word out on Ryan’s indefensible record, and building momentum to ensure victory on Election Day," he added.

Zerban is formerly a Kenosha County supervisor, and he is wealthy from running a catering business. Zerban had a healthy $500,000 in cash on hand on his July 27 pre-primary fundraising report. Still, it paled in comparison to Ryan's $5.4 million in cash on hand in his pre-primary report.

The Wisconsin primary is Tuesday. Both Zerban and Ryan are unopposed.

It is not unusual for vice presidential candidates to seek two offices at once. Sen. Joe Lieberman (I-Conn.) continued his Senate campaign as Al Gore's Democratic running mate in 2000, and then-Sen. Biden (Del.) did the same while on Obama's 2008 ticket.